Explosive elements



Feb. 24, 1970 A. SILVIA ET AL EXPLOSIVE ELEMENTS Filed May 29, 1.967

INVENTORS 3,496,868 EXPLOSIVE ELEMENTS Denis A. Silvia, Shalimar, Fla.,and Richard T. Ramsey, Fredericksburg, Va., assignors to the UnitedStates of America as represented by the Secretary of the Navy Filed May29, 1967, Ser. No. 644,432 Int. Cl. F4211 3/00; F42b 3/00 US. Cl. 102-228 Claims ABSTRACT OF THE DISCLOSURE Improved explosive elements capableof performing explosive logic and switching operations consisting of acontinuous explosive network suitable for die manufacture. The inherentdifiiculty of thin explosive trails in propagating around sharp corners,is utilized in constructing the network.

Cross-reference to related applications This application is animprovement over pending application Ser. No. 468,676, filed June 30,1965, for Explosive Circuits, by Denis A. Silvia, and is a furtherimprovement over pending application Ser. No. 637,866, filed May 3, 1967for Explosive Gate, Diode and Switch, by Denis A. Silvia et al. and nowPatent No. 3,430,564.

Background of the invention.

The present invention relates generally to improved explosive elementsfor performing logic operations and, more particularly, to a continuousexplosive network utilizing, for its operation, the reluctance of thinexplosive trails in propagating around sharp corners.

In the above-mentioned application, Ser. No. 468,676, an explosivedestructive cross-over is constructed from a pair of intersectingexplosive-filled trails having gaps at the intersection forming ajunction or island. Consumption of the explosive in the island, frompropagation through a leg of one trail, prevents further propagationtherethrough from a leg of the other trail. As an improvement over thisexplosive circuit, the above-cited Explosive Gate, Diode and Switch wasdeveloped in which point contacts between secondary explosive trails areused, in lieu of the gaps, for performing logic operations. While bothof these techniques have performed satisfactorily in the laboratory, theuse of gaps and mechanical contacts posed problems of reliability andease of manufacture. The instant invention, therefore, attempts toobviate the difiiculties posed by the prior art, by means of acontinuous explosive network thereby replacing the need for mechanicalcontacts and gaps. Factors of greater control, less weight andcomplexity, and greater efficiency, of the explosive circuitry, areaccordingly achieved.

Summary of the invention The present invention improves upon thereliability, simplicity, and effectiveness of the prior art explosivecircuit devices, by utilizing a continuous explosive network of acomparatively thin cross-section. The criticality of the trails gaps andpoint contacts, in the above-mentioned applications, is obviated whenthe intersecting trails are made continuous. An explosive destructivecross-over is produced by arranging a pair of trails in intersectingrelation whereby one trail terminates in full communication with aconstricted or necked-down area of the other trail. Propagation alongthe constricted trail is prevented at the necked-down area, if the othertrail is detonated first. A portion of the constriction is therebyconsumed without any hazard in permitting detonation along theconstricted trail since the detonation cannot be negotiated around sharpcorners. In like manner, an explosive diode is constructed from a singleexplosive trail having a porate 3,496,868 Patented Feb. 24, I970 tion ofits length narrower than its remaining portion. Detonation from thewider end first is incapable of continuing along the narrower portionbecause of its inherent inability to turn into it. One-way propagation iaccordingly allowed only if detonation proceeds first along the narrowsection. Also, these two explosive elements easily give rise to theconstruction of an explosive switch and other explosive circuitry.

It is therefore an object of the present invention to provide anexplosive element whereby explosive circuitry is simplified and madeeasier to manufacture.

Another object of the instant invention is to provide explosive elementswhich will be considerably sophisticated over existing explosivecircuitry at little cost.

A further object of the present invention is to provide improvedexplosive elements of greater reliability when used for complex decisioncircuitry.

A still further object of the invention is to provide explosive elementswhich form a continuous network and perform by simply utilizing a knowninherent characteristic whereby explosive gates and diodes may beconstructed.

Other objects, advantages and novel features of the present inventionwill be come apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

Brief description of the drawings FIG. 1 illustrates an example of themanner in which the detonation wave leaves a section of explosiveundetonated upon turning a corner;

FIG. 2 illustrates the manner in which the detonation cuts itself offwhen the trail into which the detonation is turning is too narrow;

FIG. 3 illustrates an explosive gate according to the present invention;

FIG. 4 is the same explosive gate as that of FIG. 3 except thatdetonation is initiated from a different trail;

FIG. 5 is an explosive diode according to the present invention; and

FIG. 6 is the same explosive diode as that of FIG. 5 except thatdetonation has been initiated differently.

Description of the preferred embodiments In each of the above-mentionedrelated designs, an explosive circuit of sufiicient workability wasproduced, but only after extreme caution had been exercised inconstructing the critical trail dimensions, gaps, spacings, pointcontacts, etc. In addition, thicknesses of approximately 0.085 inch wererequired in order that the detonation be properly negotiated aroundsharp corners. In the interest of reducing the amount of explosive inthe trails for weight-saving purposes, the trail thicknesses are hereinreduced to approximately 0.025 inch. With such trail dimensions,however, it was observed that propagation around sharp corners wasrendered impossible because the detonation wave left a quantity ofundetonated explosive as it turned the corner. It therefore cut itselfolf by is failure to negotiate around the corner.

Referring therefore to FIG. 1 of the drawings, there is shown a simpleexplosive element, preceding the instant design, in which thiscutting-off by the detonation wave was observed. FIG. 1 illustrates aplate 10 of inert material with an explosive trail A and an explosivetrail B provided thereon. These trails may be constructed by forming achannel or grooves in the plate 10 and filling them with an explosivesuch as Du Pont EL506C, or by fabricating the trail using the Du Pontsheet explosive. The plates in all the figures of the instant design areso constructed, as are the plates of the two co-pending relatedapplications. In FIG. 1 herein, as well as in the remaining figures, thethickness of each trail is approxi- 3 mately 0.025 inch and thedirection of detonation is illustrated by arrows and represented by wavelines. Propagation along trail A in FIG. 1 was found capable ofnegotiating around the corner to B only when trail B was madesignificantly wider than trail A. During the course of turning, however,the detonation wave left a quantity of explosive undetonated as at 11.It was further observed that, should the trail width, such as B, be of adimension substantially equal to A, the detonation would cut itself off.Attention, therefore, is called to FIG. 2 of the drawings in which aplate 20 of inert material is provided with trails A and B thereon.Detonation propagates along trail A and, as it begins to negotiatetowards B, a quantity 21 of the explosive fails to detonate. The entirewidth of the trail B was found to be cut off thereby preventing furtherpropagation. This unique inherent quality of relatively thin layers ofsheet explosive trails suggested the construction of the constructivecross-over or gate as clearly shown in FIG. 3 of the drawings. A plate30 is therein shown provided with a trail A and a trail B-B' thereon.This explosive gate is similar to that gate found in application Ser.No. 637,866 except that the point contact has been completelyeliminated. In lieu of the critical point contact, the trail A hassimply been necked-down as at 32 and has been allowed to open into thetrail B-B' such that complete communication of explosive now existsbetween the two trails. Trail BB' is constructed with a notch 34 and aconstricted portion 33. Also, the explosive width at constriction 33 isless than the minimum thickness for sustained detonation such thatdetonation will be dying while passing through 33. The length ofconstriction 33 is also short enough such that sustained detonation israpidly recovered after passing therethrough. Because the detonation isdying in 33, it is thereby easily stopped by breaking from explosivetrail A, which will be hereinafter discussed. Detonation along trail B-Btherefore, in either direction, will continue uninterrupted, ifdetonation along trail A is initiated after B-B'. Because the trailscommunicate with each other, the detonation has a tendency to propagatetowards A. Due to its inherent reluctance to turn sharp corners,however, a portion, as at 3.1, will not be detonated from B-B aspropagation passes by trail A. On the other hand, should propagationcommence along trail A first, see FIG. 4, the constriction at 33 will bethereby consumed and propagation along trail B-B', will be prohibited,thus forming the explosive destructive cross-over. Tendency of thedetonation wave to proceed toward either B or B is impeded because ofits inherent inability to turn sharp corners. In addition, thenecked-down construction of A, at 32, permits consumption of only asmall portion of area 33 and further prevents a turning from A into B orB. Portions 35 of trail B-B' are therefore left undetonated from trailA.

An explosive diode is capable of being easily constructed according tothe present design, as on plate 40 in FIG. 5. There, an explosive trailC-D is provided having a narrow portion 42 at which detonation iscommenced. Since the portion at D is significantly wider, propagationfrom C is capable of turning toward D without cutting itself off. Only aquantity at 41 is left undetonated along the trail. Propagation from Dtoward C, however, FIG. 6, produces a cutting off of the detonationwave, as at 43, since the trail into which the wave is turning is toonarrow and negotiation of the turn is inherently impossible.

In accordance with the disclosed explosive elements, the explosiveswitch can be easily constructed and any form of explosive circuit canbe produced without difficulty.

From the above, it can be seen that improved explosive elements havebeen designed, in the form of continuous networks, for increasing theirreliability, efiiciency, and ease of manufacture. More importantly, theinability of the explosive to negotiate around sharp corners is takenadvantage of for producing the elementary explosive gate and explosivediode. From an economic standpoint, the invention creates significantcost and weight savings because of the use of a thin explosive trail notheretofore possible. The instant explosive elements are basically simpleand therefore manufacture is essentially non-critical. They have apotential application in many explosive advance items and, as in theabovementioned explosive circuit applications, permit an elimination ofa large number of safe-arm devices with no reduction in reliability.Particular application of the instant invention are, for example, forwarhead escape systems, missile systems, explosive munitions, demolitioncharges, and the like.

What is claimed is:

1. An improved explosive element for performing logic operationscomprising a support plate of inert material having thereon a continuousnetwork of explosive trails including at least a first explosive trailand a second explosive trail in intersecting communication with saidfirst trail, there being a sharp turn in said network at theintersection of said first and second trails, said first trail beingsufficiently thin, at least in the area of said intersection, that adetonation front, proceeding first along said second trail is inherentlyincapable of turning said sharp turn into said first trail.

2. The element of claim 1 wherein said trails intersect to form anL-shaped continuous network.

3. The element of claim 1 wherein said network is made up of shallow,explosive-filled grooves on a surface of said support plate.

4. The element of claim 1 wherein said network is made up of strips ofsheet explosive.

5. The element of claim 1 wherein said first trail and said second trailextend in the same direction and are joined by said sharp turn inend-to-end relation, whereby, an explosive diode results, as adetonation front can travel through said network solely in the directionfrom said first trail to said second trail.

6. The element of claim 1 wherein said first and second trails intersectto form a T-shaped continuous network, said first trail being the toppart of the T, whereby an explosive null gate results as a detonationfront, proceeding first along said second trail, consumes a portion ofsaid first trail, thereby preventing a detonation front from proceedingthrough the first trail.

7. The element of claim 1 wherein said second trail, at the juncture ofsaid intersecting trails, is necked-down so as to consume only a minimumportion of said first trail.

8. The element of claim 6 wherein said first trail is relatively widenear both of its ends and thin near its middle.

References Cited UNITED STATES PATENTS 3,095,812 7/1963 Coursen 102273,175,491 3/1965 Robertson 10227 3,311,055 3/1967 Stresau et al 102-223,368,485 2/1968 Klotz 10227 VER'LIN R 'PENDEGRASS, Primary Examiner

